Celebrity lips: Real or fake?

We asked msnbc.com contributor Dr. Tony Youn, a Michigan-based, board-certified plastic surgeon who is the author of the new memoir "In Stitches," has been featured on "Dr. 90210" and runs a popular celebrity cosmetic surgery blog, to weigh in on which celebrities' lips are real or fake.

Dr. Youn, who hasn't treated any of those featured, shares his observations:

Scarlett Johansson’s lips have surpassed Angelina Jolie’s as being the most kissable -- and requested -- in Hollywood. They are naturally full, sensual, and help make her a classic bombshell. A lot of patients ask me to make their lips look like Scarlett’s, but it’s impossible for a plastic surgeon to create perfection like this.

Beyonce is the total package. All the single ladies would love to have her lips! While I speculate she’s had a breast augmentation and a nose job, her lips look amazingly real. No need for needles or Restylane here! If she came into my office requesting a lip enhancement, I would turn her down. No use messing with perfection!

During one of her recent court hearings, Lindsay’s lips looked like two bed-length pillows. They were unnaturally plump, with the upper and lower lips the same size. Between acting gigs, rehab and jail, how does she find the time to have a plastic surgeon inject her lips?

Lara’s lips look like two sausages, still in their natural casing. The natural proportions of her lips appear to be altered. In most people, the lower lip is naturally 50 percent larger than the upper lip. For Lara, her lower lip is actually smaller than her upper lip. This is why they look so strange and unnatural. Lara’s lips are the classic Trout Pout. I suspect that she’s had placement of a permanent implant into her lips, like Gortex. I have Gortex in my jacket.

Megan Fox is this generation’s Angelina Jolie, just without the Oscar and the naturally full lips. While you can’t buy an Oscar, you can buy full lips, which is exactly what Megan appears to have done. It looks to me that she has transformed her lips into quite possibly the sexiest in Hollywood. No one shows off her pouty lips like Megan. Bravo to her plastic surgeon!

I always suspected that Kim had naturally full lips, like Angelina Jolie, Scarlett Johansson, and Beyonce Knowles. Then one day I saw some photos of them looking like they’d been stung by a hive of bees. Kim has denied the rumors, but photos don’t lie. Her butt may be real, her hair may be real, but her lips… not so much. They look great though.

America’s Sweetheart has become America’s poster child for overdone lips. Ever since she appeared in "My Mom’s New Boyfriend," my blog www.celebcosmeticsurgery.com has been inundated with comments about her unnaturally puffy lips. Her upper lip looks stiff and larger than her lower lip. This may be due to a permanent implant, such as silicone. Unless the silicone was injected, it should be easily removed in a 20 minute surgery. Then she can go back to looking like the woman we fell in love with in "Sleepless in Seattle" and "When Harry Met Sally."

Demi has naturally thin lips. If you check her out in "Ghost," my favorite movie of hers, you can see that her upper lip is very thin. Today it’s still on the thin side, but slightly fuller than it used to be. I believe she gets very conservative lip injections by a top-flight Beverly Hills plastic surgeon. The natural proportions are maintained and the lips aren’t overdone. While I doubt she’s had the $3 million of plastic surgery some have speculated, a few hundred bucks here and there on her lips is definitely possible.

I never thought Jennifer had work done on her lips until I saw a before-and-after photo on a website. While I’m still not 100 percent certain she’s had them injected, it’s definitely possible. Her lips look unnaturally full, but not overdone.

No one has ever really mentioned Eva’s lips before, but they just might be the most attractive feature of this very attractive actress. They appear untouched by a plastic surgeon’s knife, and are full, pouty, and sensual. While not as plump as Scarlett Johansson’s or Angelina Jolie’s, Eva’s lips are my favorite on this list. Many housewives are desperate for lips like Eva’s. She looks like she’d pass the Kiss Test. What’s the Kiss Test? It’s the best way to tell whether a woman has had her lips injected. You kiss her lips and if they feel like two rubber tires, she fails. I’m sure Eva would pass.

What a disaster. Nadya Suleman has 14 children, including her octuplets, no job, yet still she is able to get her lips plumped and her tummy tucked. Who does this for her? The reason why people suspect that she’s trying to look like Angelina Jolie is because her lips are almost Angelina’s size. Well, just like you can’t turn a Pinto into a Porche, you can’t turn Octomom into Angelina. A tip from me to her: skip the lip injections and buy your kids some savings bonds for college.

Angelina has the most famous lips in the world. The envy of women for years, her lips appear totally natural and unaltered by plastic surgery. Older photos of her show the same plump, gorgeous lips that she has today. Even losing a bunch of weight a few years ago didn’t make her lips smaller. While she may have abdicated her throne of “Most Kissable Lips” to Scarlett Johannssen, her lips still remain her calling card.

Julia Roberts may have the most attractive lips of all time. Like millions of other men, I fell in love with her smile the moment I first saw it in "Pretty Woman." Her smile is natural but she single-handedly started the collagen lip injection craze back in 1990, which has now evolved into the Restylane and Juvederm lip injection craze of today. Julia’s lips are the classic standard of beauty in Hollywood. She has a smile prettier than the Mona Lisa.

Priscilla’s lips look scarily like Jack Nicholson’s Joker. They are turned up at the corners and overly large. In addition to injections of Restylane, she may also have had an overdone "grin lift," which lifts the corners of the mouth. There are reports that she was injected with industrial strength liquid silicone by a renegade phony doctor, who has since been arrested.

Nicole’s lips are like her acting. Sometimes they are amazing, and other times not so much. When she has them conservatively enhanced, her lips rival the most kissable in Hollywood. When she overdoes them, she looks like she can’t drink through a straw. My best advice for Nicole: Go easy on the injections. Sometimes less is more.

Suzanne has been all over the place promoting her books about aging gracefully. But has she had help from the knife? Her lips look plumper than Chrissy’s from "Three’s Company." I suspect she’s had injections of either fat or Juvederm to augment them. Some even speculate that she’s had stem cells injected into her face. Could she have had stem cell lip injections too? She’s not admitting to it!

Click here to read an excerpt of Dr. Tony Youn's new memoir "In Stitches" about becoming a cosmetic surgeon.